Modern diagnostic medicine has benefited significantly from radiology, which is the use of radiation, such as x-rays, to generate images of internal body structures. In general, to create an x-ray image, x-ray beams are passed through the body and absorbed, in varying amounts, by tissues in the body. An x-ray image is created based on the relative differences in the transmitted x-ray intensities.
Techniques are known through which x-ray images are used to locate the real-time position of surgical instruments in the patient anatomy represented by the x-ray image without requiring x-rays to be continually taken. In one such system, as disclosed in U.S. Pat. No. 5,772,594 to Barrick, light emitting diodes (LEDs) are placed on a C-arm fluoroscope x-ray imager, on a drill, and on a reference bar positioned on the bone to be studied. A three-dimensional optical digitizer senses the position of the LEDs, and hence the position of the drill, the C-arm fluoroscope, and the object bone. Based on this information, the real-time position of the drill in anatomy represented by the x-ray image is determined, and a corresponding representation of the drill in the x-ray image is displayed. This allows the surgeon to continually observe the progress of the surgery without necessitating additional x-ray images.
Surgical navigational guidance, as discussed above, can provide a tool for helping the physician perform surgery. It is an object of the present invention to provide several enhancements to traditional surgical navigational guidance techniques.